Tag Archives: bees

Quantum dots as pollen labels: tracking pollinators

Caption: This bee was caught after it visited a flower of which the pollen grains were labelled with quantum dots. Under the microscope one can see where the pollen was placed, and actually determine which insects carry the most pollen from which flower. Credit: Corneile Minnaar

Fascinating, yes? Next, the news and, then, the video about the research,

A February 14, 2019 news item on ScienceDaily announces research from South Africa,

A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method to track pollen for over a century.

A February 13, 2019 Stellenbosh University press release (also on EurekAlert but published February 14, 2019) by Wiida Fourie-Basson, which originated the news item, expands on the theme,

In an article published in the journal Methods in Ecology and Evolution this week, Dr Corneile Minnaar describes this novel method, which will enable pollination biologists to track the whole pollination process from the first visit by a pollinator to its endpoint – either successfully transferred to another flower’s stigma or lost along the way.

Despite over two hundred years of detailed research on pollination, Minnaar says, researchers do not know for sure where most of the microscopically tiny pollen grains actually land up once they leave flowers: “Plants produce massive amounts of pollen, but it looks like more than 90% of it never reaches stigmas. For the tiny fraction of pollen grains that make their way to stigmas, the journey is often unclear–which pollinators transferred the grains and from where?”

Starting in 2015, Minnaar decided to tread where many others have thus far failed, and took up the challenge through his PhD research in the Department of Botany and Zoology at Stellenbosch University (SU).

“Most plant species on earth are reliant on insects for pollination, including more than 30% of the food crops we eat. With insects facing rapid global decline, it is crucial that we understand which insects are important pollinators of different plants–this starts with tracking pollen,” he explains.

He came upon the idea for a pollen-tracking method after reading an article on the use of quantum dots to track cancer cells in rats (https://doi.org/10.1038/nbt994). Quantum dots are semiconductor nanocrystals that are so small, they behave like artificial atoms. When exposed to UV light, they emit extremely bright light in a range of possible colours. In the case of pollen grains, he figured out that quantum dots with “fat-loving” (lipophilic) ligands would theoretically stick to the fatty outer layer of pollen grains, called pollenkitt, and the glowing colours of the quantum dots can then be used to uniquely “label” pollen grains to see where they end up.

The next step was to find a cost-effective way to view the fluorescing pollen grains under a field dissection microscope. At that stage Minnaar was still using a toy pen from a family restaurant with a little UV LED light that he borrowed from one of his professors.
“I decided to design a fluorescence box that can fit under a dissection microscope. And, because I wanted people to use this method, I designed a box that can easily be 3D-printed at a cost of about R5,000, including the required electronic components.” (view video at https://youtu.be/YHs925F13t0

[or you can scroll down to the bottom of this post]

So far, the method and excitation box have proven itself as an easy and relatively inexpensive method to track individual pollen grains: “I’ve done studies where I caught the insects after they have visited the plant with quantum-dot labelled anthers, and you can see where the pollen is placed, and which insects actually carry more or less pollen.”
But the post-labelling part of the work still requires hours and hours of painstaking counting and checking: “I think I’ve probably counted more than a hundred thousand pollen grains these last three years,” he laughs.

As a postdoctoral fellow in the research group of Prof Bruce Anderson in the Department of Botany and Zoology at Stellenbosch University, Minnaar will continue to use the method to investigate the many unanswered questions in this field.

Here’s a link to and a citation for the paper,

Using quantum dots as pollen labels to track the fates of individual pollen grains by Corneile Minnaar and Bruce Anderson. Methods in Ecology and Evolution DOI: https://doi.org/10.1111/2041-210X.13155 First published: 25 January 2019

This paper is behind a paywall.

Here is the video,

Please, don’t kill my hive! (a Science Rap Academy production)

In celebration of an upcoming event in Vancouver (Canada), “Honey, Hives, and Poetry,” I’m including this April 17, 2015 news from David Bruggeman (on his Pasco Phronesis blog),

Tom McFadden has debuted the first video of this year’s Science Rap Academy.  Seventh and eighth grade students at the Nueva School prepare a music video based on a science concept, usually reworking a rap or hip-hop song.

Here’s the first installment in this year’s Science Rap Academy series, Please Don’t Kill My Hive,

There are many posts on this blog about Tom McFadden and his various science rap projects (many of them courtesy of David Bruggeman/Pasco Phronesis). Here’s one of the more recent ones, a May 30, 2014 posting.

Getting back to David’s April 17, 2015 news, he also mentions the latest installment of  “Science goes to the movies” which features three movies (Kingsman: The Secret Service, The Lazarus Effect, and Them!) and has Neil deGrasse Tyson as a guest. David has embedded the episode on his blog. One brief comment, it’s hard to tell how familiar Tyson or the hosts, Faith Salie and Dr. Heather Berlin are with the history of the novel or science. But the first few minutes of the conversation suggest that Mary Shelley’s Frankenstein is the first novel to demonize scientists. (I had the advantage of not getting caught up in their moment and access to search engines.) Well, novels were still pretty new in Europe and I don’t believe that there were any other novels featuring scientists prior to Mary Shelley’s work.

A brief history of novels: Japan can lay claim to the first novel, The Tale of Genji, in the 11th century CE, (The plot concerned itself with aristocratic life and romance.) Europe and its experience with the novel is a little more confusing. From the City University of New York, Brooklyn site, The Novel webpage,

The term for the novel in most European languages is roman, which suggests its closeness to the medieval romance. The English name is derived from the Italian novella, meaning “a little new thing.” Romances and novelle, short tales in prose, were predecessors of the novel, as were picaresque narratives. Picaro is Spanish for “rogue,” and the typical picaresque story is of the escapades of a rascal who lives by his wits. The development of the realistic novel owes much to such works, which were written to deflate romantic or idealized fictional forms. Cervantes’ Don Quixote (1605-15), the story of an engaging madman who tries to live by the ideals of chivalric romance, explores the role of illusion and reality in life and was the single most important progenitor of the modern novel.

The novel broke from those narrative predecessors that used timeless stories to mirror unchanging moral truths. It was a product of an intellectual milieu shaped by the great seventeenth-century philosophers, Descartes and Locke, who insisted upon the importance of individual experience. They believed that reality could be discovered by the individual through the senses. Thus, the novel emphasized specific, observed details. It individualized its characters by locating them precisely in time and space. And its subjects reflected the popular eighteenth-century concern with the social structures of everyday life.

The novel is often said to have emerged with the appearance of Daniel Defoe’s Robinson Crusoe (1719) and Moll Flanders (1722). Both are picaresque stories, in that each is a sequence of episodes held together largely because they happen to one person. But the central character in both novels is so convincing and set in so solid and specific a world that Defoe is often credited with being the first writer of “realistic” fiction. The first “novel of character” or psychological novel is Samuel Richardson’s Pamela (1740-41), an epistolary novel (or novel in which the narrative is conveyed entirely by an exchange of letters). It is a work characterized by the careful plotting of emotional states. Even more significant in this vein is Richardson’s masterpiece Clarissa (1747-48). Defoe and Richardson were the first great writers in our literature who did not take their plots from mythology, history, legend, or previous literature. They established the novel’s claim as an authentic account of the actual experience of individuals.

As far as I’m aware none of these novels are concerned with science or scientists for that matter. After all, science was still emerging from a period where alchemy reined supreme. One of the great European scientists, Isaac Newton (1642-1726/7), practiced alchemy along with his science. And that practice did not die with Newton.

With those provisos in mind, or not, do enjoy the movie reviews embedded in David’s April 17, 2015 news.  One final note,David in his weekly roundup of science on late night tv noted that Neil deGrasse Tyson’s late night tv talk show, Star Talks, debuted April 20, 2015, the episode can be seen again later this week while deGrasse Tyson continues to make the rounds of other talk shows to publicize his own.

Vive Nano and the American Chemistry Council Award and a philosphy of awards

Vive Nano recently received a 2011 Responsible Care Performance Award from the American Chemistry Council. From the May 11, 2011 news release,

The Responsible Care Performance Award recognizes those member companies who excelled at helping ACC meet industry-wide safety and product stewardship targets. ACC Responsible Care award winners qualify based on exemplary performance, and are selected by an external expert committee. Other award winners this year include Chevron Phillips Chemical Company, ExxonMobil Chemical Company, Nova Chemicals and Honeywell.

At this point I want to make a distinction between Vive Nano’s acceptance of the award and the award’s credibility and to make a personal confession. First the confession, I don’t probe too deeply when I win award and I probably should. Now onto the issue of an award’s credibility. Something in the news release caught my attention,

“Responsible Care is the chemical industry’s commitment to sustainability, enabling us to enhance environmental protection and public health, as well as improve worker safety and plant security,” said Greg Babe, chair of ACC’s Board Committee on Responsible Care and president and CEO of Bayer Corp. [emphases mine]

One of the Bayer companies (Babe is the Chief Executive Officer of the parent corporation), Bayer CropScience has a product used as a pesticide which has been strongly implicated as a factor in the calamitous collapse of bee colonies in North America and elsewhere. From a Dec. 14, 2010 article by Ariel Schwartz for Fast Company,

Beekeepers across the U.S. are reporting record low honey crops as their bees fail to make it through the winter. One-third of American agriculture, which relies on bee pollination, is at stake. And the problem may be at least partially attributable to clothianidin, a Bayer-branded pesticide used on corn and other crops.

But as we revealed last week, the EPA knew that clothianidin could be toxic when the product came on the market in 2003. So why is it still on the market?

The bee-toxic pesticide problem can be traced back to 1994, when the first neonicotinoid pesticide (Imidacloprid) was released. Neonicotinoids like imidacloprid and clothianidin disrupt the central nervous system of pest insects, and are supposed to be relatively non-toxic to other animals. But there’s a problem: The neonicotinoids coat plant seeds, releasing insecticides permanently into the plant. The toxins are then released in pollen and nectar–where they may cause bees to become disoriented and die.

….

The EPA first brought up the link between clothianidin and bees before the pesticide’s release in February 2003. The agency originally planned to withhold registration of the pesticide because of concerns about toxicity in bees, going so far as to suggest that the product come with a warning label (PDF): “This compound is toxic to honey bees. The persistance [sic] of residues and the expression clothianidin in nectar and pollen suggest the possibility of chronic toxic risk to honey bee larvae and the eventual stability of the hive.”

But in April 2003, the EPA decided to give Bayer conditional registration. Bayer could sell the product and seed processors could freely use it, with the proviso that Bayer complete a life cycle study of clothianidin on corn by December 2004. Bayer was granted an extension until May 2005 (and permission to use canola instead of corn in its tests), but didn’t complete the study until August 2007. The EPA continued to allow the sale of clothianidin, and once the Bayer study finally came out, it was flawed.

There’s more about the bees and Bayer both in this article and in a Dec. 17, 2010 article by Schwartz for Fast Company.

Here’s an excerpt from the company’s Dec. 22, 2010 response to the concerns,

Bayer CropScience was recently made aware of an unauthorized release [emphasis mine] from within the Environmental Protection Agency (EPA) of a document regarding the seed treatment product, clothianidin, which is sold in the United States corn market. Bayer CropScience disagrees with the claims by some environmental groups against this product and we believe these are incorrect and unwarranted with regard to honey bee concerns.

The study referenced in the document is important research, conducted by independent experts and published in a major peer-reviewed scientific journal. The long-term field study conducted in accordance with Good Laboratory Practices (GLP) by independent experts using clothianidin-treated seed showed that there were no effects on bee mortality, weight gain, worker longevity, brood development, honey yield and over-winter survival. The EPA reviewed and approved the study protocol prior to its initiation and it was peer-reviewed and published in the Journal of Economic Entomology*. Upon reviewing the results of the long-term trial, the Agency noted the study as “scientifically sound and satisfies the guideline requirements for a field toxicity test with honey bees.

According to Schwartz, the ‘unauthorized release’ was in response to a freedom of information (FOI) query.

If the product is suspected of being unsafe, why not make the data available for analysis by respected scientists who are not associated with Bayer in any way? Given the magnitude of the problem, shouldn’t the company go above and beyond? And, what does this mean for its commitment to the American Chemistry Council’s Responsible Care program?

The issue is not Vive Nano; it’s the credibility of the award. For example, the Nobel Peace Prize is funded from the proceeds of a fortune derived from the invention of dynamite, amongst other things. (I was not able to confirm that Alfred Nobel was a munitions manufacturer although I’ve heard that any number of times.) Does the source for the funding matter or has the Nobel Peace Prize accrued credibility over the years from the reputations of the award recipients?

Could Vive Nano and companies like it (assuming they are genuinely living up to the standards of the Responsible Care program) possibly give the award credibility over time?

There you have it. An award is not just an award; it is a complex interplay between the recipient, the organization giving the award, and reputation.